The UMTS radio interface is subdivided into three protocol layers: the physical layer as Layer 1, the data link layer including MAC, RLC, BMC, PDCP as Layer 2 and the network layer with RRC as Layer 3. Within the protocol structure of the UMTS air interface, a radio resource control RRC in the radio network control entity RNC is responsible for the control and allocation of radio resources for all user equipment located in a radio cell. Resource management is currently performed on a relatively slow time basis because the corresponding signaling between the user equipment and the RNC is effected via the RRC messages.
An essential task of the MAC-d entity in the MAC layer in the transmitter is, in the transmit case, to map the data applied via the dedicated logical channels above the MAC layer to the dedicated transport channels of the physical layer. In the receiver, the task of the Mac-d is to distribute the data received on the dedicated transport channels to the dedicated logical channels. In the receive case, the MAC-d entity again distributes the data received via the dedicated transport channels to the relevant dedicated logical channels. On the transport channels, the data is transmitted in the form of fixed-length packet units, the so-called transport blocks. With regard to the further standardization and evolution of UMTS within the Third Generation Partnership Project or 3GPP bodies, improvements for fast and efficient data transmission via the dedicated transport channel are needed.